Chemical Kinetics

Question

If the experiment below is run for 60 s, 0.16 mol A remain. Which of the following statements is or are true?

 

After 60 s there are 0.84 mol B in the flask.
The decrease in the number of moles of A from t1 = 0 to t2 = 20 s is greater than that for t1 = 40 to t2 = 60 s.
The average rate for the reaction from t1 = 40 to t2 = 60 s is 7.0×10−3 M/s.

PICTURE HERE: http://i67.tinypic.com/34ye2a9.png

a. Only one of the statements is true
b. Statements I and II are true
c. Statements I and III are true
d. Statements II and III are true
e. All three statements are true

Answer 1

Hi, Connie,

 

You can check all three statements easily:

1. The first one is a simple math--you started with 1.0 mole of A and it seems the reaction has 1-1 ratio, so if only 0.16 moles of A is left, then 0.84 moles of B must have been produced.

2. Just check the difference in A from t=0 to t=20 and compare it with the difference when t=40 to t=60. What did you get for those differences?

3. Finally, if we assume the average rate to be 0.007 M/s we can calculate the gain in B (or loss in A) over those 20 seconds between times t=40 and t=60. Compare it to the actual difference that we know from picture and #1.

 

Let me know if you need more help with this.

 

Victor

Answer 2

The picture doesn't show up for me. More information is needed than given here.